Preparative monitoring apparatus for operation of a press

ABSTRACT

A preparative monitoring apparatus for operations of a press displays interlock conditions relating to an operation currently in operation whose establishment is indespensable for the operation to be performed as well as the title of this operation. These interlock conditions are displayed by means of light emitting elements and the title is displayed by a display device provided on a panel. When either one of these interlock conditions is unestablished, the light emitting element corresponding to the unestablished condition and the display of the title are caused to flicker, thereby indicating occurrence of abnormality in the press.

BACKGROUND OF THE INVENTION

The present invention relates to a preparative monitoring apparatus for operation of a press.

Usually, any press operation is initiated only after it is confirmed that all interlock conditions with respect to an intended press operation such as slide adjustment, preparation for operation or the like have been completely established and if not, necessary remedial activities have been practiced until all of the interlock conditions are established.

In a prior art, a display as to the interlock conditions established prior to starting a press operation as well as a display that the required preparative operations for a press have been completed are undertaken by means of a display apparatus as illustrated in FIG. 1. A panel P_(a1) includes a board B on which a variety of operations and interlock conditions are indicated. Further, a plurality of lamps LP are arranged on the board B in the form of a matrix in conformance with the respective operations and interlock conditions. Thus, the conventional display apparatus as mentioned above informs that the preparative operations have been completed when all the lamps corresponding to the intended operation are lit and thereafter one of preparation completion lamps L_(f1) to L_(f4) is lit, after all the interlock conditions corresponding to the intended operation have been established.

However, it is found with the conventional display apparatus that as the type and number of operations and interlock conditions increase, the number of lamps increases correspondingly and thereby an increased area is required for a panel, resulting in a necessity for a wider space where it is placed. Another drawback inherent to the conventional display apparatus is that it is manufactured at an expensive cost due to the arrangement of plural lamps corresponding to a certain interlock condition.

SUMMARY OF THE INVENTION

The present invention is intended to obviate the drawbacks with the conventional display apparatus as mentioned above.

Thus, it is an object of the present invention to provide a preparative monitoring apparatus for operation of a press which is characterized in that a title of a certain press operation is presented by means of display devices, that a plurality of lighting elements are provided which are adapted to be turned on so as to display the interlock conditions corresponding to said press operation, and that said lighting elements and display devices are intermittently turned on so as to present an existence of abnormality that the intended interlock conditions have been not established.

Another object of the present invention is to provide a preparative monitoring apparatus for operation of a press in which an area required for a display panel of the monitoring apparatus is substantially reduced.

Still another object of the present invention is to provide a preparative monitoring apparatus for operation of a press in which, when it is necessary to change the existing interlock conditions corresponding to a modified press operation, all that is to be done is to change or modify the content stored in the storage circuit in conformance with the changed interlock conditions without any necessity for increasing an area for the display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings,

FIG. 1 shows a display panel of a conventional preparative monitoring apparatus for operation of a press;

FIG. 2 is a block diagram illustrating a preparative monitoring apparatus in accordance with an embodiment of the present invention;

FIG. 3 shows a display panel of a preparative monitoring apparatus in accordance with an embodiment of the present invention;

FIG. 4 is a block diagram illustrating a comparison circuit, a display control circuit relative to indication of interlock conditions and a display circuit for the preparative monitoring apparatus of the present invention; and

FIG. 5 is a block diagram illustrating a display control circuit relative to indication of the title of a press operation as well as a display circuit for the preparative monitoring apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Now the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIG. 2, when any one of press operation switches (not shown) is turned on, a corresponding operation switch signal D_(a1) enteres a memory circuit 3 as an input signal D₁ by way of an input circuit 1. Then, a comparison signal D₃ relative to the interlock conditions of the intended operation enteres a comparison circuit 4 in response to the signal D₁ which has entered the memory circuit 3, whereas a letter group display signal D₄ enteres a display control circuit 5 for the purpose of displaying the title of the intended press operation.

Further, an interlock condition signal D_(a2) generated in the press machine enters the comparison circuit 4 as a comparison signal D₂ by way of an input circuit 2. The comparison circuit 4 is constructed such that a comparison is made between the comparison signal D₃ representing a reference interlock conditions and the comparison signal D₂ representing the existing interlock conditions, and outputs a lighting signal D₅ for lighting lighting elements wich present interlock conditions corresponding to the press operation into a display control circuit 5. It should be noted that said lighting signal D₅ includes a signal which serves for intermittently activating said lighting lamp corresponding to interlock conditions which are not established.

The display control circuit 5 generates a display driving signal D₆ on the basis of both the display signal D₄ and the lighting signal D₅ and then said display driving signal D₆ enteres a display circuit 6. This display circuit 6 displays the interlock conditions as well as the title of the intended press operation in response to the entered signal D₆. When it is found that an interlock condition is not established, the same is identified by way of intermittent lighting and at the same time the title of the press operation corresponding to it is also lit intermittently.

FIG. 3 illustrates how a display is effected by the display circuit 6. A panel P_(a2) includes display boards B_(a1) and B_(a2) on which a number of interlock conditions are indicated. Further, the panel P_(a2) includes a plurality of lighting elements L₁ and L_(n) such as light emitting diodes or the like which are located at a predetermined position corresponding to the respective interlock conditions (it should be noted that the suffix n shows the number of interlock conditions and lighting elements L₉ to L.sub.(n-2) are omitted from the drawing). Furthermore, the panel P_(a2) includes a plurality of display devices L_(t1) to L_(tm) at the bottom part thereof which are intended to present the title of the press operations (it should be noted that the suffix m shows the number of letters which represent the title of the press operation and display devices L_(t6) to L_(t)(m-1) are omitted from the drawing). The display devices L_(t1) to L_(tm) are typically a 5×7 matrix type display device on which any letter display is available, for instance, English alphabets.

FIG. 4 illustrates the comparison circuit 4, the display control circuit 5 relative to designation of the respective interlock conditions and the display circuit 6.

The operations of these circuits will be described below typically with reference to a safety block (one of the interlock conditions). When both the signals D₂ and D₃ relative to the safety block are "1", an exclusive OR circuit E_(x1) and an AND circuit A₁ receives signal "1" respectively. Thus, the exclusive OR circuit E_(x1) becomes inoperative and the AND circuit A₁ becomes operative, whereby a transistor T_(r1) is turned on to light the lighting element L₁.

On the other hand, when both the signals D₂ and D₃ relative to the safety lock are "0", both the exclusive OR circuit E_(x1) and the AND circuit A₁ becomes inoperative, whereby the transistor T_(r1) is turned off and the lighting element L₁ is deenergized.

When the safety block condition is not established due to abnormality such as machine failure or the like and thereby the signals D₂ and D₃ relative to the safety block do not coincide with each other, the exclusive OR circuit E_(x1) becomes operative and the AND circuit A₁ becomes inoperative. As a result, the AND circuit A_(a1) is caused to operate at a frequency t₁ at which a pulse generator 7 generates an output pulse P₁. Thus, the transistor T_(r1) is turned on and off at the frequency t₁ of the pulse P₁ and thereby the lighting element L₁ is lit intermittently.

Since the exclusive OR circuit E_(x1) becomes operative, a signal S_(e) by which the display for indicating the title of the press operation is intermittently lit enters the display control circuit 5 by way of the OR circuit O_(a).

As described above, when the signals D₂ and D₃ representative of the reference and existing interlock conditions are identified by "1", the corresponding lighting elements L₁ to L_(n) are turned on, whereas when these signals are "0", the lighting elements are turned off. On the other hand, when the signals D₂ and D₃ do not coincide with each other, the lighting elements L₁ to L_(n) corresponding to the interlock conditions are intermittently turned on and at the same time the signal S_(e) is produced so that the display for the title of the press operation is intermittently turned on. It should be noted that exclusive OR circuits E_(x3) to E_(x)(n-1), AND circuits A₃ to A.sub.(n-1), A_(a3) to A_(a)(n-1), OR circuits O₃ to O.sub.(n-1) and transistors T_(r3) to T_(r)(n-1) are omitted from FIG. 4.

FIG. 5 illustrates the display control circuit 5 and the display circuit 6 relative to the display devices L_(t1) to L_(tm).

In FIG. 5, it is assumed that the signal S_(e) is not produced by the comparison circuit 4, in the die unclamping operation. During the period of die clamping, an AND circuit A_(b) is kept inoperative and a transistor Ta is turned off, whereby AND circuits A_(c1) to A_(cm) become operative (AND circuits A_(c4) to A_(c)(m-1) are omitted from the drawing).

The memory circuit 3 is constructed such that the letter group display signal D₄ corresponding to the input signal D₁ (corresponding to the die unclamping operation in this case) enteres a matrix driving signal generating circuit 9.

The matrix driving signal generating circuit 9 generates a matrix driving signal D₇ on the basis of the entered letter group display signal D₄ for representing the title of the press operation with the aid of English letters ("DIE UNCLAMP" in this case) and then the matrix driving signal D₇ enters all the display devices L_(t1) to L_(t2) at the same time. Further, the matrix driving signal 9 issues a synchronizing signal SY to a timing signal generating circuit 10 every time when a lighting signal D₇ equivalent to a single English letter enters the display deivdes L_(t1) to L_(tm).

Every time when the synchronizing signal SY is inputted, the timing signal generating circuit 10 generates a timing signal which is in turn issued to the AND circuits A_(c1) to A_(cm) one after another to activate them so that transistors T_(b1) to T_(bm) are turned on one after another.

In case it is intended to display the title of a press operation "DIE UNCLAMP", the first alphabet "D" is displayed by means of the display device L_(t1) when the lighting signal D₇ corresponding to the alphabet "D" enters the display devices L_(t1) to L_(tm) and thereby the transistor T_(b1) is turned on; the second alphabet "1" is displayed by means of the display device L_(t2) when the lighting signal D₇ corresponding to the alphabet "L" enteres the display devices L_(t1) to L_(tm) and thereby the transistor T_(b2) is turned on; and then the same steps are repeated in conformance with the order of alphabets constituting the title of the press operation "DIE UNCLAMP". It should be noted that an arrangement is made such that the transistor T_(bm) is turned on and thereafter the transistor T_(b1) is turned on.

Once it is detected by means of the comparison circuit 4 that the existing interlock condition is deviated from a reference one, the signal S_(e) enteres the AND circuit A_(b) and thereby the AND circuit A_(b) is turned on at a frequency t₂ at which the pulse generator 8 generates the output pulse P₂ so that the transistor T_(a) is turned on at the frequency t₂ of the pulse P₂. Thus, all the AND circuits A_(c1) to A_(cm) are turned off at the frequency t₂ of the pulse P₂ and then all the transistors T_(b1) to T_(bm) are turned off at the frequency t₂ of the pulse P₂. As a result a display of the display devices L_(t1) to L_(tm) is intermittently activated.

It should be noted that the frequency of the synchronizing signal SY is determined within such an extent that no fluctuation takes place when practicing a display by means of the display devices L_(tl) to L_(tm) and the frequency t₂ of the output pulse P₂ generated by the pulse generator 8 is determined sufficiently lower than the frequency of the synchronizing signal SY.

It will be readily apparent that the title of a press operation can be presented in Katakana alphabet (Japanese alphabet) or other alphabets when the display device for representing the title of the press operation is replaced with another one which is designed to display such alphabet and the letter group display signal D₄ in the memory circuit is modified to cope with display of such alphabet. 

What is claimed is:
 1. A preparative monitoring apparatus for operation of a press wherein interlock conditions relating to a press operation are displayed during said press operation, comprising:a display circuit including a plurality of lighting elements for displaying said interlock conditions and a display device for performing display of title of selected operation; memory means for storing a plurality of reference interlock conditions corresponding to a type of press operation, establishment of said reference interlock conditions being indispensable for said press operation; and a control circuit for comparing said reference interlock conditions with an actually established interlock conditions and for flickering said lighting elements corresponding to interlock conditions which do not coincide with said reference interlock conditions.
 2. A preparative monitoring apparatus for operation of a press as defined in claim 1, further comprising a flickering circuit for flickering said display of title of selected operations if at least one of the interlock conditions corresponding to said selected operations is not established. 